Coastal Zone Changes in West Africa: Challenges and Opportunities for Satellite Earth Observations

Abstract

The West African coastal population and ecosystems are increasingly exposed to a multitude of hazards. These are likely to be exacerbated by global climate change and direct impacts from local human activities. Our ability to understand coastal changes has been limited by an incomplete understanding of the processes and the difficulty of obtaining detailed data. Recent advances in satellite techniques have made it possible to obtain rich coastal data sets that provide a solid foundation for improving climate change adaptation strategies for humanity and increasing the resilience of ecosystems for sustainable development. In this article, we review West African coastal layout and current socio-environmental challenges together with key parameters that can be monitored and several coastal management programs that rely on satellite techniques to monitor indicators at the regional level. The social, technical and scientific problems and difficulties that hinder the interest of coastal practitioners and decision-makers to use the satellite data are identified. We provide a roadmap to precisely respond to these difficulties and on how an improved satellite earth observation strategy can better support future coastal zone management in West Africa.

Extreme coastal water levels with potential flooding risk at the low-lying Saint Louis historic city, Senegal (West Africa)

“…Durand et al (2010) the sandspit and water levels in Saint-Louis lagoon are increasingly aligned with the rhythm of the tides. However, due to the lack of long-term tide gauges in Saint Louis, more generally along the African coast (Abessolo Ondoa et al, 2019;Marti et al, 2021;Almar et al, 2022), our current study is limited by the use of the FES2014 tide data which are harmonic-based, off-shore, and do not reflect change over time (Figure 5D); any trends or changes in local tides in could not be determined. Our results also show interannual variability in the temporal occurrence of extreme water levels at Saint-Louis.…”

Exploring coastal bathymetry retrieval for ocean modeling: a case study from West Africa

“…Our understanding of coastal change has been hindered by an incomplete understanding of the underlying processes, but also crucially by the challenges of acquiring detailed data (Abessolo et al, 2023). Yet recent advances in satellite technology have made it possible to collect comprehensive coastal datasets (Almar et al, 2023;Benveniste et al, 2019;Melet et al, 2020;Turner et al, 2021), raising hopes of new advances for adaptation strategies and sustainable development in the South (Dada et al, 2021(Dada et al, , 2024. These advances need to move beyond the development phase and be put to the test in realistic applications, in order to demonstrate their usefulness and the progress still to be made.…”

African coastal camera network efforts at monitoring ocean, climate, and human impacts

“…Moreover, altimetry, which measures sea surface variations, is still limited to areas a few km from the coast because of inappropriate sensors for the nearshore. While satellite earth observation represents a real opportunity to monitor African coasts 37 , they face several challenges, including the lack of ground truth observations. Buoys allow the measurement of hydrodynamic parameters (e.g., waves, sea level, and currents) closest to the coast, but they are almost non-existent or unavailable along the African coasts.…”